Merge pull request #309 from monnand/race-controller

fix data races in controller

pkg/controller/replication_controller_test.go

@@ -435,17 +435,18 @@ func TestWatchControllers(t *testing.T) {
 	fakeEtcd := util.MakeFakeEtcdClient(t)
 	manager := MakeReplicationManager(fakeEtcd, nil)
 	var testControllerSpec api.ReplicationController
-	receivedCount := 0
+	received := make(chan bool)
 	manager.syncHandler = func(controllerSpec api.ReplicationController) error {
 		if !reflect.DeepEqual(controllerSpec, testControllerSpec) {
 			t.Errorf("Expected %#v, but got %#v", testControllerSpec, controllerSpec)
 		}
-		receivedCount++
+		close(received)
 		return nil
 	}
 
 	go manager.watchControllers()
-	time.Sleep(10 * time.Millisecond)
+
+	fakeEtcd.WaitForWatchCompletion()
 
 	// Test normal case
 	testControllerSpec.ID = "foo"
@@ -456,14 +457,14 @@ func TestWatchControllers(t *testing.T) {
 		},
 	}
 
-	time.Sleep(10 * time.Millisecond)
-	if receivedCount != 1 {
-		t.Errorf("Expected 1 call but got %v", receivedCount)
+	select {
+	case <-received:
+	case <-time.After(10 * time.Millisecond):
+		t.Errorf("Expected 1 call but got 0")
 	}
 
 	// Test error case
 	fakeEtcd.WatchInjectError <- fmt.Errorf("Injected error")
-	time.Sleep(10 * time.Millisecond)
 
 	// Did everything shut down?
 	if _, open := <-fakeEtcd.WatchResponse; open {
@@ -472,9 +473,8 @@ func TestWatchControllers(t *testing.T) {
 
 	// Test purposeful shutdown
 	go manager.watchControllers()
-	time.Sleep(10 * time.Millisecond)
+	fakeEtcd.WaitForWatchCompletion()
 	fakeEtcd.WatchStop <- true
-	time.Sleep(10 * time.Millisecond)
 
 	// Did everything shut down?
 	if _, open := <-fakeEtcd.WatchResponse; open {

pkg/util/fake_etcd_client.go

@@ -18,6 +18,7 @@ package util
 
 import (
 	"fmt"
+	"sync"
 	"testing"
 
 	"github.com/coreos/go-etcd/etcd"
@@ -29,6 +30,9 @@ type EtcdResponseWithError struct {
 }
 
 type FakeEtcdClient struct {
+	condWatchCompleted *sync.Cond
+	condLock           sync.Mutex
+
 	Data        map[string]EtcdResponseWithError
 	DeletedKeys []string
 	Err         error
@@ -44,10 +48,24 @@ type FakeEtcdClient struct {
 }
 
 func MakeFakeEtcdClient(t *testing.T) *FakeEtcdClient {
-	return &FakeEtcdClient{
+	ret := &FakeEtcdClient{
 		t:    t,
 		Data: map[string]EtcdResponseWithError{},
 	}
+	// There are three publicly accessible channels in FakeEtcdClient:
+	//  - WatchResponse
+	//  - WatchInjectError
+	//  - WatchStop
+	// They are only available when Watch() is called.  If users of
+	// FakeEtcdClient want to use any of these channels, they have to call
+	// WaitForWatchCompletion before any operation on these channels.
+	// Internally, FakeEtcdClient use condWatchCompleted to indicate if the
+	// Watch() method has been called. WaitForWatchCompletion() will wait
+	// on condWatchCompleted. By the end of the Watch() method, it will
+	// call Broadcast() on condWatchCompleted, which will awake any
+	// goroutine waiting on this condition.
+	ret.condWatchCompleted = sync.NewCond(&ret.condLock)
+	return ret
 }
 
 func (f *FakeEtcdClient) AddChild(key, data string, ttl uint64) (*etcd.Response, error) {
@@ -97,12 +115,22 @@ func (f *FakeEtcdClient) Delete(key string, recursive bool) (*etcd.Response, err
 	return &etcd.Response{}, f.Err
 }
 
+func (f *FakeEtcdClient) WaitForWatchCompletion() {
+	f.condLock.Lock()
+	defer f.condLock.Unlock()
+	f.condWatchCompleted.Wait()
+}
+
 func (f *FakeEtcdClient) Watch(prefix string, waitIndex uint64, recursive bool, receiver chan *etcd.Response, stop chan bool) (*etcd.Response, error) {
 	f.WatchResponse = receiver
 	f.WatchStop = stop
 	injectedError := make(chan error)
+
 	defer close(injectedError)
 	f.WatchInjectError = injectedError
+
+	f.condWatchCompleted.Broadcast()
+
 	select {
 	case <-stop:
 		return nil, etcd.ErrWatchStoppedByUser